This paper reports how to utilize a virtual simulation environment embedding a dynamic process simulator for the purpose of process operation and control system design in industrial production systems. It also aims for the integrated engineering environment including all process life cycle phases such as process design, engineering, implementation, and maintenance. Virtual simulation environment using rigorous model based dynamic simulator, multi-variable model predictive optimizing control and online optimizer covering large process unit, has been developed and applied to the fluid catalytic cracking unit control. Effectiveness of the environment has been confirmed from the viewpoint of not only process engineering but also control engineering. Virtual simulation environment is also applicable to the evaluation of other operation and control systems.